Re: [PATCH 2/3] usb: dwc3: qcom: Add interconnect support in dwc3 driver

[Georgi Djakov <georgi.djakov@linaro.org>]

Hi Chandana,

Thank you for the patch!

On 9/11/19 07:54, Chandana Kishori Chiluveru wrote:
> Add interconnect support in dwc3-qcom driver to vote for bus
> bandwidth.
> 
> This requires for two different paths - from USB master to
> DDR slave. The other is from APPS master to USB slave.
> 
> Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>
> ---
>  drivers/usb/dwc3/dwc3-qcom.c | 147 ++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 145 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> index 184df4d..4b8c2ae 100644
> --- a/drivers/usb/dwc3/dwc3-qcom.c
> +++ b/drivers/usb/dwc3/dwc3-qcom.c
> @@ -14,6 +14,7 @@
>  #include <linux/extcon.h>
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
> +#include <linux/interconnect.h>
>  #include <linux/phy/phy.h>
>  #include <linux/usb/of.h>
>  #include <linux/reset.h>
> @@ -38,6 +39,9 @@
>  #define PWR_EVNT_LPM_IN_L2_MASK			BIT(4)
>  #define PWR_EVNT_LPM_OUT_L2_MASK		BIT(5)
>  
> +#define USB_DDR "usb-ddr"
> +#define APPS_USB "apps-usb"

What is the benefit of adding these defines? Please remove them.

>  struct dwc3_qcom {
>  	struct device		*dev;
>  	void __iomem		*qscratch_base;
> @@ -59,8 +63,13 @@ struct dwc3_qcom {
>  	enum usb_dr_mode	mode;
>  	bool			is_suspended;
>  	bool			pm_suspended;
> +	struct icc_path *usb_ddr_icc_path;
> +	struct icc_path *apps_usb_icc_path;

Nit: Maybe try to make the indentation style consistent with the existing code?

>  };
>  
> +static int usb_interconnect_enable(struct dwc3_qcom *qcom);
> +static int usb_interconnect_disable(struct dwc3_qcom *qcom);
> +
>  static inline void dwc3_qcom_setbits(void __iomem *base, u32 offset, u32 val)
>  {
>  	u32 reg;
> @@ -222,7 +231,7 @@ static void dwc3_qcom_enable_interrupts(struct dwc3_qcom *qcom)
>  static int dwc3_qcom_suspend(struct dwc3_qcom *qcom)
>  {
>  	u32 val;
> -	int i;
> +	int i, ret;
>  
>  	if (qcom->is_suspended)
>  		return 0;
> @@ -234,6 +243,11 @@ static int dwc3_qcom_suspend(struct dwc3_qcom *qcom)
>  	for (i = qcom->num_clocks - 1; i >= 0; i--)
>  		clk_disable_unprepare(qcom->clks[i]);
>  
> +	/* Remove bus voting */
> +	ret = usb_interconnect_disable(qcom);
> +	if (ret)
> +		dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
> +
>  	qcom->is_suspended = true;
>  	dwc3_qcom_enable_interrupts(qcom);
>  
> @@ -259,6 +273,11 @@ static int dwc3_qcom_resume(struct dwc3_qcom *qcom)
>  		}
>  	}
>  
> +	/* Add bus voting */
> +	ret = usb_interconnect_enable(qcom);
> +	if (ret)
> +		dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
> +
>  	/* Clear existing events from PHY related to L2 in/out */
>  	dwc3_qcom_setbits(qcom->qscratch_base, PWR_EVNT_IRQ_STAT_REG,
>  			  PWR_EVNT_LPM_IN_L2_MASK | PWR_EVNT_LPM_OUT_L2_MASK);
> @@ -409,6 +428,116 @@ static int dwc3_qcom_clk_init(struct dwc3_qcom *qcom, int count)
>  	return 0;
>  }
>  
> +/* Interconnect path bandwidths in KBps */
> +#define USB_MEMORY_AVG_HS_BW 240000
> +#define USB_MEMORY_PEAK_HS_BW 700000
> +#define USB_MEMORY_AVG_SS_BW  1000000
> +#define USB_MEMORY_PEAK_SS_BW 2500000
> +#define APPS_USB_AVG_BW 0
> +#define APPS_USB_PEAK_BW 40000

I would suggest to wrap the values with kBps_to_icc() or MBps_to_icc() macro.

> +
> +/**
> + * usb_interconnect_init() - Request to get interconnect path handle
> + * @qcom:			Pointer to the concerned usb core.
> + *
> + */
> +static int usb_interconnect_init(struct dwc3_qcom *qcom)
> +{
> +	struct device *dev = qcom->dev;
> +
> +	qcom->usb_ddr_icc_path = of_icc_get(dev, USB_DDR);
> +	if (IS_ERR(qcom->usb_ddr_icc_path)) {
> +		dev_err(dev, "Error: (%ld) failed getting %s path\n",
> +			PTR_ERR(qcom->usb_ddr_icc_path), USB_DDR);
> +		return PTR_ERR(qcom->usb_ddr_icc_path);
> +	}
> +
> +	qcom->apps_usb_icc_path = of_icc_get(dev, APPS_USB);
> +	if (IS_ERR(qcom->apps_usb_icc_path)) {
> +		dev_err(dev, "Error: (%ld) failed getting %s path\n",
> +				PTR_ERR(qcom->apps_usb_icc_path), APPS_USB);
> +		return PTR_ERR(qcom->usb_ddr_icc_path);
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * geni_interconnect_exit() - Request to release interconnect path handle
> + * @qcom:			Pointer to the concerned usb core.
> + *
> + * This function is used to release interconnect path handle.
> + */
> +static void usb_interconnect_exit(struct dwc3_qcom *qcom)
> +{
> +	icc_put(qcom->usb_ddr_icc_path);
> +	icc_put(qcom->apps_usb_icc_path);
> +}
> +
> +/* Currently we only use bandwidth level, so just "enable" interconnects */
> +static int usb_interconnect_enable(struct dwc3_qcom *qcom)
> +{
> +	struct dwc3 *dwc;
> +	int ret;
> +
> +	dwc = platform_get_drvdata(qcom->dwc3);
> +	if (!dwc) {
> +		dev_err(qcom->dev, "Failed to get dwc3 device\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	if (dwc->maximum_speed == USB_SPEED_SUPER) {
> +		ret = icc_set_bw(qcom->usb_ddr_icc_path,
> +			USB_MEMORY_AVG_SS_BW, USB_MEMORY_PEAK_SS_BW);
> +		if (ret)
> +			return ret;
> +	} else {
> +		ret = icc_set_bw(qcom->usb_ddr_icc_path,
> +			USB_MEMORY_AVG_HS_BW, USB_MEMORY_PEAK_HS_BW);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = icc_set_bw(qcom->apps_usb_icc_path,
> +		APPS_USB_AVG_BW, APPS_USB_PEAK_BW);
> +	if (ret)
> +		goto err_disable_mem_path;
> +
> +	return 0;
> +
> +err_disable_mem_path:
> +	icc_set_bw(qcom->usb_ddr_icc_path, 0, 0);
> +
> +	return ret;
> +}
> +
> +/* To disable an interconnect, we just its bandwidth to 0 */

Missing the word "set"?

> +static int usb_interconnect_disable(struct dwc3_qcom *qcom)
> +{
> +	struct dwc3 *dwc = platform_get_drvdata(qcom->dwc3);
> +	int ret;
> +
> +	ret = icc_set_bw(qcom->usb_ddr_icc_path, 0, 0);
> +	if (ret)
> +		return ret;
> +
> +	ret = icc_set_bw(qcom->apps_usb_icc_path, 0, 0);
> +	if (ret)
> +		goto err_reenable_memory_path;
> +
> +	return 0;       /* Success */

Nit: This comment seems useless.

> +
> +	/* Re-enable things in the event of an error */
> +err_reenable_memory_path:
> +	if (dwc->maximum_speed == USB_SPEED_SUPER)
> +		icc_set_bw(qcom->usb_ddr_icc_path,
> +			USB_MEMORY_AVG_SS_BW, USB_MEMORY_PEAK_SS_BW);
> +	else
> +		icc_set_bw(qcom->usb_ddr_icc_path,
> +			USB_MEMORY_AVG_HS_BW, USB_MEMORY_PEAK_HS_BW);
> +
> +	return ret;
> +}
>  static int dwc3_qcom_probe(struct platform_device *pdev)
>  {
>  	struct device_node	*np = pdev->dev.of_node, *dwc3_np;
> @@ -494,6 +623,17 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
>  		goto depopulate;
>  	}
>  
> +	ret = usb_interconnect_init(qcom);
> +	if (ret) {
> +		dev_err(dev, "failed to get interconnect handle ret:%d\n", ret);
> +		goto depopulate;
> +	}
> +	ret = usb_interconnect_enable(qcom);
> +	if (ret) {
> +		dev_err(qcom->dev, "bus bw voting failed %d\n", ret);
> +		goto interconnect_exit;
> +	}
> +
>  	qcom->mode = usb_get_dr_mode(&qcom->dwc3->dev);
>  
>  	/* enable vbus override for device mode */
> @@ -503,7 +643,7 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
>  	/* register extcon to override sw_vbus on Vbus change later */
>  	ret = dwc3_qcom_register_extcon(qcom);
>  	if (ret)
> -		goto depopulate;
> +		goto interconnect_exit;
>  
>  	device_init_wakeup(&pdev->dev, 1);
>  	qcom->is_suspended = false;
> @@ -513,6 +653,8 @@ static int dwc3_qcom_probe(struct platform_device *pdev)
>  
>  	return 0;
>  
> +interconnect_exit:
> +	usb_interconnect_exit(qcom);
>  depopulate:
>  	of_platform_depopulate(&pdev->dev);
>  clk_disable:
> @@ -540,6 +682,7 @@ static int dwc3_qcom_remove(struct platform_device *pdev)
>  	}
>  	qcom->num_clocks = 0;
>  
> +	usb_interconnect_exit(qcom);
>  	reset_control_assert(qcom->resets);
>  
>  	pm_runtime_allow(dev);
>
The patch looks ok, but does not apply to neither mainline or linux-next.

Thanks,
Georgi